We don't go anywhere. We just attain a degree of enlightenment. Nirvana means extinction. Extinction of what? Ultimately having to take uncontrolled rebirth because of karma. But in our life, we can attain the extinction of negative mindstates and the extinction of karma. The general Zen view of this is that practice itself is enlightenment and we can attain a form of nirvana directly during zazen (or practice in general). And this is true, btw. However Zen also trains us to take the degree of realization that we have back into our interactions in the world.

"To search for enlightenment or nirvana beyond this mind is impossible. The reality of your own self-nature the absence of cause and effect, is what’s meant by mind. Your mind is nirvana."

"Not suffering another existence is reaching the Way. Not creating delusions is enlightenment. Not engaging in ignorance is wisdom. No affliction is nirvana."

"The impartial Dharma is only practiced by great bodhisattvas and Buddhas. To look on life as different from death or on motion as different from stillness is to be partial. To be impartial means to look on suffering as no different from nirvana,, because the nature of both is emptiness. By imagining they’re putting an end to Suffering and entering nirvana Arhats end up trapped by nirvana. But bodhisattvas know that suffering is essentially empty. And by remaining in emptiness they remain in nirvana. Nirvana means no birth and no death. It’s beyond birth and death and beyond nirvana. When the mind stops moving, it enters nirvana. Nirvana is an empty mind."

So it appears that you don't go anywhere, you just stop making delusions.

One should not kill any living being, nor cause it to be killed, nor should one incite any other to kill. Do never injure any being, whether strong or weak, in this entire universe!

"To search for enlightenment or nirvana beyond this mind is impossible. The reality of your own self-nature the absence of cause and effect, is what’s meant by mind. Your mind is nirvana."

"Not suffering another existence is reaching the Way. Not creating delusions is enlightenment. Not engaging in ignorance is wisdom. No affliction is nirvana."

"The impartial Dharma is only practiced by great bodhisattvas and Buddhas. To look on life as different from death or on motion as different from stillness is to be partial. To be impartial means to look on suffering as no different from nirvana,, because the nature of both is emptiness. By imagining they’re putting an end to Suffering and entering nirvana Arhats end up trapped by nirvana. But bodhisattvas know that suffering is essentially empty. And by remaining in emptiness they remain in nirvana. Nirvana means no birth and no death. It’s beyond birth and death and beyond nirvana. When the mind stops moving, it enters nirvana. Nirvana is an empty mind."

So it appears that you don't go anywhere, you just stop making delusions.

thank you

what I understand it . In Zen . Even if I Attain Nirvana I still born again in this life ?

Please see this thread about the Mahayana understanding of nirvana (including Zen) : Apratishtita Nirvana. That's how non-abidance is the essential path and goal of Zen, both sudden enlightenment and the path of the bodhisattva.

"There is no such thing as the real mind. Ridding yourself of delusion: that's the real mind."(Sheng-yen: Getting the Buddha Mind, p 73)

In fact in zen sansara and nirvana are inseperable...As Dogen said:http://www.stanford.edu/group/scbs/sztp ... shogi.htmlSimply understand that birth and death are in themselves nirvana; there is no birth and death to be hated nor nirvana to be desired. Then, for the first time, we will be freed from birth and death. To master this problem is of supreme importance.